Submission date: 5 May 2017

Abstract:

We show that every free amalgamation class of finite structures with relations and (symmetric) partial functions is a Ramsey class when enriched by a free linear ordering of vertices. This is a common strengthening of the Nešetřil-Rödl Theorem and the second and third authors' Ramsey theorem for finite models (that is, structures with both relations and functions). We also find subclasses with the ordering property. For languages with relational symbols and unary functions we also show the extension property for partial automorphisms (EPPA) of free amalgamation classes. These general results solve several conjectures and provide an easy Ramseyness test for many classes of structures.

Mathematics Subject Classification: Primary: 05D10, 20B27, Secondary: 03C15, 22F50, 37B05 ACM-class: G.2.2; F.4.1

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Full text arXiv 1705.02379: pdf, ps.